(1) Field of Invention
This invention relates to novel methods for preparing fluorinated organic compounds, and more particularly to methods of producing fluorinated olefins.
(2) Description of Related Art
Hydrofluorocarbons (HFC's), in particular hydrofluoroalkenes such tetrafluoropropenes (including 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf) and 1,3,3,3-tetrafluoro-1-propene (HFO-1234ze)) and pentafluoropropenes (1,2,3,3,3-pentafluoropropene (HFO-1225ye) have been disclosed to be effective refrigerants, fire extinguishants, heat transfer media, propellants, foaming agents, blowing agents, gaseous dielectrics, sterilant carriers, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, displacement drying agents and power cycle working fluids. Unlike chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), both of which potentially damage the Earth's ozone layer, HFCs do not contain chlorine and thus pose no threat to the ozone layer.
Several methods of preparing hydrofluoroalkanes are known. For example, U.S. Pat. No. 5,679,875 discloses methods for manufacturing 1,1,1,2,3-pentafluoropropene and 1,1,1,2,3-pentafluoropropane; U.S. Pat. No. 6,031,141 discloses a catalytic process using chromium-containing catalysts for the dehydrofluorination of hydrofluorocarbons to fluorooolefins; U.S. Pat. No. 5,396,000 discloses a process for producing CF3CHFCH2F utilizing a vapor phase catalytic dehydrofluorination step to produce CF3CF═CHF from CF3CHFCHF2; U.S. Pat. No. 6,548,719 discloses a process for producing fluoroolefins by dehydrohalogenating a hydrofluorocarbon in the presence of a phase transfer catalyst; U.S. Publication No. 2006/0106263 discloses the production and purification of hydrofluoroolefin compounds; and WO98/33755 discloses catalytic process for the dehydrofluorination of hexafluoropropanes to pentafluoropropenes.
Notwithstanding prior teachings applicants appreciate a continuing need for methods of efficiently preparing certain hydrofluorocarbons, particularly pentafluorpropenes such as HFO-1225, including particularly HFO-1225ye.